Project Summary Despite remarkable advancements in HIV science and markedly increasing access to essential HIV services worldwide, we are at a critical juncture in the HIV response. We are witnessing an alarming shift in risk and disease burden towards key populations and other vulnerable groups. While some of the inequities in access to prevention and treatment that underly these disparities are due to policy challenges, a concerted research effort is required to increase and expand available options, particularly with a view to those that are low cost to facilitate scale up and deepen our understanding of efficient and successful implementation approaches. Science is needed for evidence-based, effective and equitable tools to achieving both epidemic control and universal access to essential services. IAS 2019 will be the key global scientific convening to review progress against remaining challenges in controlling the epidemic just one year before the global targets of reducing new infections and the number of AIDS-related deaths to less than 500,000 per year, and to eliminate HIV-related discrimination. To this end the conference will facilitate rapid translation of new science into practice and define course corrections for HIV research on the path towards control of the epidemic and sustained adherence support for those living with HIV. Emphasis will be placed on the integration of basic science into clinical practice and the use of data for higher operational efficiency. IAS 2019, taking place in Mexico City from 21-24 July 2019, has an expected attendance of 6,000 delegates from more than 125 countries. It will shine a spotlight on the Latin American experience where impressive progress has been made over the past ten years in increasing the number of people who know their HIV status and receive treatment, and where commitment to funding the HIV response is strong. Mexico has a long history of leadership in coordinating and funding a robust HIV response that spans training, research and south to south exchange, and includes innovation in the way state institutions work together and with civil society. The specific aims of IAS 2019 are to: 1. Accelerate basic science to shape the advancement and application of innovative technologies across the HIV prevention, and treatment cascade, including pathogenesis, transmission, vaccines, remission and a cure; 2. Accelerate updates to treatment guidance especially for low and middle-income countries, including pharmacovigilance in pregnant women, infected children and HIV-exposed, uninfected children; 3. Fast-track consolidated responses to HIV co-infections (notably TB and viral hepatitis) and to emerging co-morbidities and other non-communicable diseases; 4. Strengthen HIV prevention research to improve biomedical, behavioral and structural interventions; 5. Advance core components of implementation science research that address the challenges and opportunities of integration across a range of epidemic settings; 6. Address HIV vulnerability and determinants of disease progression among key and marginalized populations, including novel interventions and implementation science to reduce stigma and discrimination. The scientific program will consist of four tracks: Track A ? Basic Science; Track B ? Clinical Science; Track C ? Prevention Science; and Track D ? Social, Behavioral, and Implementation Research. Cross-cutting aspects will be covered in plenary talks that also connect the scientific tracks with community and leadership perspectives, and bridging sessions will cut across at least two of the tracks to provide opportunities for multi- disciplinary dialogues. The participation of young researchers, basic scientists and researchers in related fields such as non-communicable diseases will be strengthened by active solicitation of relevant science and the provision of specific financial support, in addition to increased remote-access options. Key science from the conference will be disseminated and discussed in regional contexts following IAS 2019.